1. Field of the Invention
The present invention relates to a rear entry type ski boot comprising a shell base and an upper, in one or two portions, which is journalled, on the shell base, around a horizontal and transverse axis.
2. Description of Background and Relevant Information
In alpine ski boots of the rear entry type having a journalled upper, the opening axis, i.e., the axis around which the upper pivots, must be positioned relatively close to the ground, for obvious kinematic reasons, so as to facilitate to the maximum the entry of the foot into the boot when the boot is put on. As in most cases, this axis also serves as a flexion axis of the upper, during skiing, the correspondence between this axis and the ankle journalled axis of the skier is not assured. In an attempt to resolve this problem, there has been provided, as will be described for example in French Patent 2,585,930, an alpine ski boot whose upper is constituted of two independent portions, namely, a front cuff and a rear spoiler, which are respectively journalled on the shell base, to their lower portions, around independent transverse pivot axes. The pivot axis of the front cuff is positioned in the zone of the malleoli, while the pivot axis of the rear spoiler is positioned at the rear with respect to the pivot axis of the front cuff. Such a boot is likewise provided with an apparatus for tightening the foot which comprises a front tightening element, longitudinally mounted with respect to the shell base, and a flexible linkage cable connecting the lower portion of this movable element to a tightening lever carried by the rear spoiler of the upper, while passing through the heel of the boot. Consequently, after the skier has tightened the upper of his boot on his lower leg, he pivots the tightening lever frontwardly in order to apply it against the rear spoiler, which causes a traction exerted on the linkage cable, a displacement towards the rear of the movable tightening element, and consequently, the foot is maintained firmly within the boot. Although such a boot facilitates the entry of the foot into the boot when the boot is put on, it has the disadvantage that, during skiing, the front cuff and rear spoiler which are pivotably mounted at their lower portions, on the shell base, around two axes which are distanced from one another, are displaced in the same way as the two movable parallel sides of a deformable parallelogram. Yet, such a displacement results in a translational movement of the front cuff and of the rear spoiler with respect to the leg which results in bothersome friction on the lower leg.